A simulation-based work order release mechanism for a flexible manufacturing system

A simulation model and real-time interface module for an operational FMS (flexible manufacturing system) facility were developed to evaluate work order release sequences on a real-time basis. Unlike most simulation studies, the evaluation is based on the transient behavior of the system and not steady-state performance. The time window in which a work order is predicted to be completed is considered in order to determine if a particular work order sequence meets due date requirements set forth by the MRP (materials requirement planning) system. In addition, results of the simulation can be used to schedule the building of fixtures and the loading of raw material. The model was successfully interfaced with the real-time control database so that initial conditions could be determined. This information is essential when looking at the transient behavior. Simulation results provide analysts with information to make improvements in the short-term schedule, resulting in better work order release decisions